HRV and sp02 sensor

[danielt]

What do you mean by a HRV sensor? In principle both PPG (optical) and ECG (electrical) sensors can be used to measure heart rate variability, although admitedly an ECG would be much more stable during exercise.

Some time ago I did find bosch sensor which would be small and low power, but I think this one I found matches these rules. It's cheap, low power, it checks for pulse and blood oxygen. https://www.banggood.com/MAX30102-Heartb...rehouse=CN

Vendor has offer me a new heartbeat sensor integrate with three LED light (Green, RED, and IR) for both heart-beat and oxygen level measure that can fit into exisitgn Pinetime case. However, I  have rejected the offer due to 1) higher sensor cost ($3-4 higher) and 2) no sure how well its work or just hype.

I still keep this as open mind. In near future, if we think oximeter is good feature (assume able to produce accurate result) to have, we can revisit this option (keep in mind this add cost).

An SpO2 sensor would be very interesting to have, especially if we can swap it to the existing Developer Units to see how well it works.

One thing that should also be discussed with the manufacturer is whether source code of a reference algorithm to derive the SpO2 values can be shared.

The community has been able to start writing its own heart rate detection algorithms for HRS3300 (I know that because I have written one myself). This is possible because heart rate is easy to confirm by other means and it is relatively easy for test subjects to change their own heart rate in order to test/calibrate the algorithm.

SpO2 is different because you cannot tell the data is "good" just by graphing it and it is also pretty challenging for a healthy person to change their SpO2 levels significantly. In fact if I read the research correctly it looks like it only drops sharply when exercising at levels right at the limit of ones physical capability. This means reference algorithms are going to be important for SpO2 sensors.